1. Technical Field
The present invention relates to seal assemblies, and more particularly, to seal assemblies which can be robotically installed around automotive vehicle windows or hatches.
2. Discussion
Seals for automotive windows or hatches are generally made of elastomeric thermosetting materials for reasons of economy and sealing effectiveness. Such elastomeric seals are made by extruding unset elastomeric material, vulcanizing or heat setting the elastomeric material and cutting to length. The seals are then generally installed on the vehicle with opposing ends in an abutting relationship. It is desirable that these seal assemblies be economical to manufacture and easy to install on the vehicle. Moreover, for satisfactory performance in the present day automotive industry, seal assemblies must effectively seal the interior of the vehicle from noise and weather elements of the external environment.
Effective sealing is made difficult where the seal must extend entirely around a window or hatch perimeter, especially where the perimeter has corners having small radii. Generally, seals which are wide enough to effectively seal without leaks tend to be difficult to install around window openings having curves with small radii. Also, once installed, due to compression and tension induced at the radii surfaces, the seal can twist resulting in an inefficient seal.
Moreover, seal assemblies extending around a window perimeter and ending in an abutting relationship have an interruption of the seal at the abutting ends whereat a potential cause for leaks is created. Thus, merely abutting ends together provides a potentially unreliable joint. However, the watertight and airtight nature of the seal can be maintained at the joint by bonding the ends together. Unfortunately, the known methods of joining the ends have major inherent disadvantages.
Currently, there are two methods of joint bonding currently being used in the industry: vulcanizing and adhesives. Vulcanizing the two ends together creates a chemically bonded joint that is normally as flexible as the parent materials. This method, however, involves high tooling costs for joint molds, capital expenditures for the plant, and high overhead costs for "work in process". The other method, adhesives, joins the ends using a cyanoacrylate adhesive effectuating a room temperature vulcanization (RTV) bond. This type of joining material tends to provide a crystalline structure joint with high failure rates. Secondary operations to fixture the joints while the adhesive is curing also involves high overhead and costs for "work in process". In short, vulcanizing or otherwise bonding ends together is expensive. Furthermore, vulcanizing or bonding the ends of the seal forms a continuous loop which is difficult for a robot to install on the automotive vehicle.
Moreover, a number of problems manifest themselves when attempting the robotic application of a closed loop seal onto an automotive vehicle opening. The problems of linear length tolerance build-up on either the seal or door assembly make reliable application difficult. Accurate length and torsional rigidity control of the seal is required for robotic installation of a seal loop. Also, sheet metal tolerances affect the overall fit of the seal assembly because the seal has defined lengths between corners. Tolerance variances can create extensive fit problems resulting in line stoppage or improperly fitted seal assemblies. Furthermore, the fact that the corners may need to be molded for rigidity adds to the complexity of the seal assembly.
Therefore, it would be desirable to provide a sealing system which eliminates the above inherent conditions in current sealing applications for automotive vehicle windows and hatches. It would further be desirable to provide a sealing system which has an elongated support channel which extends around the window perimeter. It would further be desirable to provide an elongated continuous tubular sealing member secured within the channel and wound around the perimeter of the window in overlapping relation with itself to provide an inner seal and an outer seal with a transition portion therebetween. As used herein, inner refers to a position proximate to the vehicle whereas outer refers to an adjacent position proximate to the window. It would further be desirable to provide the ends of the elongated tubular sealing member wherein they are cut at a degree .THETA. to provide an abutting surface. Moreover, it would be desirable to provide the elongated continuous sealing member ends wherein they are positioned proximate to and abutting the transition portion thereby creating an inner and outer seal such that air and water are not allowed to penetrate the dual seal configuration to enter the vehicle interior.
It would further be desirable to provide an economical seal which can be easily installed on an automotive vehicle by a robot. It would additionally be desirable to provide an elongated continuous sealing member which can be applied from a coil or magazine, extends around corners having small radii without difficulty, and which provides both an inner and outer seal. It would further be desirable to provide a sealing member which is highly resistant to leaking in that the elongated continuous sealing member extends around the window perimeter without a joint and there are no splices or molded portions likely to cause leaking. It would further be desirable to provide a seal assembly which easily adjusts for body and section variation and is unaffected by tolerance variations in the automotive sheet metal.